The invention relates generally to a feedwater heater cycle for a power plant. More particularly, the invention relates to a variable feedwater heater cycle allowing for active control of final feedwater temperature for optimal efficiency at a variety of operating conditions.
In power plants, the power output, temperature of exhausted flue gas, and efficiency are heavily impacted by adjusting a temperature of the feedwater system, i.e., the final feedwater temperature (FFWT), that enters the steam generating element, for example, a boiler in the plant. Where boilers are configured to accommodate combustion of different types of fuels, and/or operation at different loads, each set of operational conditions may require a unique final feedwater temperature (FFWT) in order to achieve maximum efficiency.